Texturing a realistic human?

Hmm painting in 3D isn't a simple thing to explain in a few lines.
You need to be more precise, give details and renders, screenshots...etc

Did you try to watch tutorials on Youtube ?
Maybe paying some from Udemy or Skillshare ?

I think that the essential thing for a render to look photorealistic has to do more with the lighting of the scene and the lights, more than the textures, but it really helps a detailed texture.

in a blender, the result is very good and realistic will soon begin to do the same people